Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison

Biogeosciences
By: , and 

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Abstract

Soil microorganisms are known to survive periods of aridity and to recover rapidly after wetting events, with the ability to transition between a dormant state in dry conditions and an active state in wet conditions. Though this dynamic behavior has been previously incorporated into soil carbon respiration modeling frameworks, a direct comparison between this active-dormant transition mechanism and a more simplified first-order model has yet to be made. Here, we demonstrate the necessary extent of model complexity needed to reproduce transient carbon respiration rates obtained from a set of soil incubation experiments implemented over a range of soil depths and time intervals. Two approaches are tested, one uses simplified first-order kinetics whereas the other employs a transition between active and dormant biomass. The performance of each model is evaluated using an Akaike Information Criterion (AIC) based on the accuracy with which they reproduce an experimental dataset consisting of two sets of time series soil incubations collected across a range of time and depth resolutions. Based on the AIC evaluation and model-data comparison, we conclude that a dormancy-enabled model featuring two distinct microbial strategists performs best for the majority of the soil profile (above 108 cm) for both high- and low- depth resolution and sampling frequency, despite the added parameters required. In contrast, the first-order model achieves better AIC scores when simulating our deepest soils (112-165 cm), where moisture fluctuations are expected to be less prevalent. These results guide how and where we choose to apply more cost intensive models.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison
Series title Biogeosciences
DOI 10.1029/2018JG004628
Volume 124
Issue 7
Year Published 2019
Language English
Contributing office(s) Geosciences and Environmental Change Science Center
Description 26 p.
First page 2222
Last page 2247